Fracture resistant connecting post



Sept. 3, 968 1.. G. c. TEURLINGS 3,400,352

FRACTURE RESISTANT CONNECTING POST Filed March 14. 1967 5 l 6 l 5 \5 g Y2 United States Patent 3,400,362 FRACTURE RESISTANT CONNECTING POSTLucas Gerardus Christianus Teurlings, Frederik, Netherlands, assignor toAMP Incorporated, Harrisburg, Pa. Filed Mar. 14, 1967, Ser. No. 623,598Claims priority, application Netherlands, Mar. 31, 1966, 6604265 7Claims. (Cl. 339-277) ABSTRACT OF THE DISCLOSURE A fiat sheet metal postsecurable in a mounting member which is provided with an apertureproximate the end securable in the mounting member to equalize thebending stress under the action of a bending force over the length ofthe apertured portion of the post and the bending stress is greater thansuch bending stress at any cross section of the remainder of the post.

Cantilever, flat sheet metal posts are commonly employed for example asconnecting posts for the attachment of electrical wire, for example bysoldering, the posts projecting from a base formed by an insulatingblock in which the posts are embedded. Since each post may project aconsiderable distance, for example half an inch from the block, it isreadily susceptible to being accidentally bent in a direction at rightangles to its plane. It has been found that these posts are susceptibleto fracture if bent as cantilevers towards the block and then bent backto their original perpendicular positions a given number of times. Thesusceptibility of the posts to fracture, results from the fact thatsince the posts act as levers under the action of the bending forces,the bending forces are greatest at the lines of entry of the posts intothe block, this being the case both when a post is bent from itsperpendicular position relative to the block and when it is bent backagain. The post is accordingly work-hardened along the line of entry inboth bending directions so that it snaps off. The susceptibility of theposts to fracture is enhanced when the posts have been stamped from arolled metal sheet transversely of the rolling direction.

An object of the invention is to provide a thin metal post capable ofwithstanding bending stresses and equalizing the bending stresses over alength thereof.

Another object of the invention is the provision of a thin metal posthaving an aperture therein to equalize bending stresses applied to thepost over the length of the apertured portion of the post.

A further object of the invention is to provide an apertured post withthe aperture located proximate an end securable in a mounting member toimprove the resistance of the post to fracture and especially if thepost is cut out perpendicularly to the rolling direction of the sheet ofmetal from which it is formed.

An additional object of the invention is the provision of a thin metalpost having an aperture therein between a longitudinal center of thepost and a base in which the post is secured and the post is dimensionedso that the cross-sectional area of the post over the length of theaperture in the direction of the longitudinal axis of the post increasestowards the base concomitantly with the mechanical advantage afforded bythe post.

Other objects and attainments of the present invention will becomeapparent to those skilled in the art upon a reading of the followingdetailed description when taken in conjunction with the drawings inwhich there is shown and described an illustrative embodiment of theinvention; it is to be understood, however, that this embodiment is notintended to be exhaustive nor limiting of the invention but is given forpurposes of illustration in order that others 3,4@,36Z Patented Sept. 3,1968 ice skilled in the art may fully understand the invention and theprinciples thereof and the manner of applying it in practical use sothat they may modify it in various forms, each as may be best suited tothe conditions of a particular use.

The invention as a preferred embodiment provides a sheet metal, flat,cantilever post extending from a base, the post having a throughaperture disposed between the longitudinal center of the post and thebase and being dimensioned so that the cross-sectional area of the postover the length of the aperture in the direction of the longitudinalaxis of the post increases towards the base concomitantly with themechanical advantage alforded by the post in respect of a force appliedto the post on the opposite side of the aperture to the base and tendingto bend the post in a direction at right angles to its plane; wherebythe bending stress under the action of the bending force is equal overthe length of the apertured portion of the post and greater than suchbending stress at any cross section of the remainder of the post.

The aperture in the post is preferably trapezoidal with the paralleledges of the aperture extending perpendicularly to the longitudinal axisof the post and the smaller end of the trapezium being directed towardsthe base. The aperture may otherwise be triangular with the apex of thetriangle directed towards the base and the base of the triangleperpendicular to the longitudinal axis of the post.

For a better understanding of the invention reference will now be madeby way of example to the accompanying drawings, in which:

FIGURE 1 is an enlarged elevational view drawn to scale, showin a sheetmetal post extending from an insulating block which is shown infragmentary form;

FIGURE 2 is an end view of FIGURE 1; and

FIGURE 3 is a view similar to FIGURE 1 which illustrates an embodiment.

A post 1 made of rolled sheet metal is fixed in a block 2 of insulatingmaterial and has a trapezoidal aperture 3, disposed between the base 2and the longitudinal center of the post 1. The parallel edges 4 and 5 ofthe apertures 3 extend perpendicularly to the longitudinal axis X of thepost, the shorter one, 5, of the two edges, being nearest the block 2.The relationships between the dimensions of the post and those of theaperture 3 and the position of the aperture 3 in the post are such thatthe cross section of the apertured portion of the post 1, i.e. over thelength 1, decreases concomitantly with the mechanical advantage affordedby the post as a cantilever in respect of a bending force applied in thedirection of the arrow A in FIGURE 2, i.e. a force tending to bend thepost 1 from its perpendicular position with respect to the block 2towards the upper (as seen in FIGURES 1 and 2) surface of the block 2,whereby the bending stress under the action of the bending force isequal over the length of the apertured portion of the post and greaterthan the bending stress in any other cross section of the post. The postwill thus bend arbitrarily about any line along the length I under theaction of the bending force since the bending stress along the length Iwill be equal throughout the length I. Let it be assumed that the post 1is first bent leftwardly (as seen in FIGURE 2) under the action of thebending force indicated by arrow A. The radius about which the post 1 isbent is large in view of the equal bending stress of the post over thelength l. The post can now be bent back to its original perpendicularposition relative to the block 2. If the post is thereafter bentrightwardly (as seen in FIGURE 2) it will bend about the sameabovementioned large radius. Thus, each time the post is bent it bendsabout the same large radius through the length I. It has been found thatthe post can be bent backwards and forwards six or seven times withoutfracturing.

In view of the improved resistance to fracture of the post, the post maybe cut out perpendicularly to the rolling direction of the sheet metalfrom which it is formed.

Instead of being trapezoidal, the aperture 3 in the post 1 may betriangular with the base of the triangle extending perpendicularly tothe longitudinal axis X of the post and the apex of the triangle beingdirected towards the base 2' as illustrated in FIGURE 3. Otherconfigurations of the aperture may, of course, be realized.

It will, therefore, be appreciated that the aforementioned and otherdesirable objects have been achieved; however, it should be emphasizedthat the particular embodiment of the invention, which is shown anddescribed herein, is intended as merely illustrative and not asrestrictive of the invention.

The invention is claimed in accordance with the following:

1. A base and a sheet metal, flat, cantilever member extending from thebase comprising a post having a through aperture disposed between alongitudinal center of the post and the base, said aperture having sidesconverging towards each other in a direction towards said base with thewidth of the aperture closest to said base being not more thanfour-fifths of the width of the aperture farthest away from the base,said post bein dimensioned so that a cross-sectional area of the postover the length of the aperture in the direction of a longitudinal axisof the post increases towards the base concomitantly with the mechanicaladvantage afforded by the post in respect of a force applied to the poston the opposite side of the aperture to the base and tending to bend thepost in a direction at right angles to its plane; whereby the bendingstress under the action of the bending force is equal over the length ofthe apertured portion of the post and greater than such bending stressat any cross section of the remainder of the post.

2. A post according to claim 1 in which the aperture is trapezoidal withparallel edges of the aperture extending perpendicularly to thelongitudinal axis of the post and a shorter one of these edges lyingnearest the base.

3. A post according to claim 1, in which the aperture is triangular witha base of the triangle extending perpendicularly to the longitudinalaxis of the post and an apex thereof being directed towards the base.

4. An electrical connection post comprising a thin metallic memberhaving one end for securing in a mounting member so that said member canextend outwardly therefrom for receiving an electrical connectionthereon, said member having an aperture therein between a longitudinalcenter of said post and said one end, said aperture having sidesconverging towards each other in a direction towards the one end withthe width of the aperture closest to said one end being not more thanfour-fifths of the width of the aperture farthest away from said one endand being dimensioned, thereby providing a cross-sectional area of saidmember over the length of said aperture in the direction of alongitudinal axis of said member, said crosssectional area increasingtowards said one end to provide an increased mechanical advantage toequalize bending stresses under the action of bending forces over thelength of the apertured section of said member and to be greater thanthe bending stresses at any cross section of the remainder of saidmember.

5. An electrical connection post according to claim 4 wherein saidaperture has a trapezoidal configuration.

6.An electrical connection post according to claim 4 wherein saidaperture has a triangular configuration,

7. An electrical connection post comprising a thin metallic memberhaving one end for securing in a mounting member so that said member canextend outwardly therefrom for receiving an electrical connectionthereon, said member having a section provided with an aperture thereinbetween a longitudinal center of said member and said one end, saidaperture having a configuration decreasing in cross section in adirection towards said one end with the width of the aperture closest tosaid one end being not more than four-fifths of the width of theaperture farthest away from said One end to provide an increasedmechanical advantage to equalize bending stresses under the action ofbending forces over the length of the apertured section and to begreater than the bending stresses at any cross section of the remainderof said member.

References Cited UNITED STATES PATENTS 2,668,279 2/ 1954 Epstein339--l03 2,923,912 2/1960 Benander 339-62 3,234,498 2/ 1966 Logan339-277 MARVIN A. CHAMPION, Primary Examiner.

R. S. STROBEL, Assistant Examiner.

